Commitments and Contingencies (Charitable Commitments) (Detail) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($)
Other Deferred Credits and Other Liabilities
Recorded Unconditional Purchase Obligation [Line Items]
Charity commitments	$ 73
Other Income
Recorded Unconditional Purchase Obligation [Line Items]
Charity expenses	$ 80

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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